Study On The Characteristics And The Mechanism Of Mountain Steppe

To reveal the characteristics and the formation mechanism of the mountain steppe community, we investigated30plots of mountain steppe community and54plots of surrounding mountain steppe community of the through the quadrat method in Wula mountain, Daqing and Manhan mountains. The composition of plant, life form and ecological water type of the mountain steppe community and its surrounding community were analyzed, and the mountain steppe with the zonal steppe and surrounding community of mountain steppe were compared respectively. The results are as follows:1. Mountain steppe is objective existence. It is not only confirmed with the definition of zonal steppe which the former Soviet scientists E.M. described, but also has the evidence of communities.2.Differences in the spatial distribution between the Mountain steppe and steppe zonation mainly due to:steppe zone is located in the plain or plateau of a semiarid areas of significant habitat domain, which belongs to horizontal zonality vegetation; while mountain steppe is mainly distributed in the larger relative height difference Mountain, which is an important part of mountain vegetation altitudinal belt in the baseband desert or desert steppe arid region, are vertical zones of vegetation; and which do not belong to the composition of mountain vegetation vertical structure in the baseband typical steppe and semi-arid areas.3. The distribution of the mountain steppe is affected by the regional climate of outside Mountain, the dominant factors forming the mountain steppe comprise distance from the inside the mountains to the mountain baseband, open degree of mountain and the relative slope.4.The degree affected by the regional climate of the outside mountains called the mountain degree, which related to the three dominant factors forming the mountain steppe. This article establishes a regression model using the three mountain steppe formation factors and the mountain degree. The mountain degree lead to the mountain altitudinal belt incomplete. But when the mountains reaches a certain range, the mountain affected by the regional climate is small enough, the mountain altitudinal belt tend to integrated, on the basis of previous two-dimensional mountain altitudinal belt theory, this paper establish a three-dimensional mountain altitudinal belt, namely:shady slope, sunny slope and the mountain degree.